The present invention relates to a water stopping method used for effecting water stopping between core wires of a sheathed wire of a wire harness, a wire harness processed by the water stopping method, and a water stopping apparatus. Incidentally, “water stopping” in the description of the present invention is not limited to the prevention of intrusion of water, but means that it effectively acts on a liquid containing water, oil, alcohol, etc., as a whole, and here description will be made using “water stopping” generally extensively used as a designation.
As a water stopping method, there is a method in which exposed core wires are immersed in a water stopping material and are filled with it (for example, see Patent Literature 1), and particularly as a method of causing a water stopping material to satisfactorily penetrate core wires, there is known one in which the air is drawn during the supply of a water stopping material or after the supply so as to reduce the pressure, thereby causing the water stopping material to penetrate into the inside of an insulating sheath (for example, see Patent Literatures 2 to 5).
As shown in FIG. 9, a sheathed wire (ground wire) 51 used in the water stopping method disclosed in the above Patent Literature 1 has an insulating sheath (sheathing material) 54 around its core wires (conductors) 53, and a terminal (ground connection terminal) 52 is press-clamped (that is, press-fastened) to one of end portions thereof.
For press-clamping the terminal 52 to the sheathed wire 51, a pair of barrels 55 of the terminal 52 are opened, and the end portion of the sheathed wire 51 where the core wires 53 have been exposed by removing the insulating sheath 54 is set on a surface between the barrels 55 of the terminal 52, and then the barrels 55 are press-fastened to be closed, thereby fixing the core wires 53 and the insulating sheath 54 to the terminal 52 by press-clamping.
In the water stopping method used for effecting water stopping between the core wires 53 of such sheathed wire 51 with the terminal 52, while effecting the pressure reducing step of drawing the air within the insulating sheath 54 from the other of the end portions of the sheathed wire 51, the water stopping material having fluidity is supplied to the one of the end portions of the sheathed wire 51 in a direction 60 of an arrow, and the water stopping material is caused to penetrate into the inside of the insulating sheath 54.
In the above water stopping method, there is adopted the vacuum pressure-reducing system for reducing the pressure by drawing the air, and therefore at the most the pressure difference more than the atmospheric pressure (1 kgf/cm2) can not be obtained. Therefore, because of the decrease of interstices between the core wires due to a small-diameter design, a lightweight design, etc., of the sheathed wire, there has been a limit to the penetration of the water stopping material.
Furthermore, it is difficult to reduce the volume of the water stopping material penetrating between the core wires.
Furthermore, at one end portions or intermediate joint portions of a plurality of sheathed wires where core wires of the plurality of sheathed wires are joined and connected together, a massive facility is required for drawing the air within a plurality of insulating sheaths from a plurality of other end portions, and therefore not only a large working space is required, but also a large facility investment is involved.
Furthermore, in the case where the sheathed wire 51 has a large diameter or in the case where a plurality of sheathed wires 51 are bundled together, the amount of the water stopping material to be used increases, and therefore the water stopping material must be additionally supplied, and besides the end portions of the core wires 53 can not completely be covered with the water stopping material, and there develop areas where the water stop material does not reach the core wires 53 of the sheathed wire 51, so that the water stopping effect is insufficient.
Furthermore, there are occasions when the water stopping material dropped on the end portions of the core wires 53 drips therefrom, and a cumbersome operation must be carried out for removing the dripped water stopping material.
Furthermore, when the water stopping material deposits on a bolt fastening plate which is to be bolt-fastened as a contact of the terminal 52, there is a fear that a defective conduction may develop at the terminal 52.                [Patent Literature 1] JP-A-11-234883        [Patent Literature 2] JP-A-2004-355851        [Patent Literature 3] JP-A-2006-202697        [Patent Literature 4] JP-A-2006-221880        [Patent Literature 5] JP-A-2006-228709        